Uptake of Atmospheric Carbon Dioxide into Silk Fiber by Silkworms

Abstract

The relation between the uptake of atmospheric CO(2) and insect's production of silk fiber has not yet been reported. Here, we provide the first quantitative demonstrations that four species of silkworms (Bombyx mori, Samia cynthia ricini, Antheraea pernyi, and Antheraea yamamai) and a silk-producing spider (Nephila clavata) incorporate atmospheric CO(2) into their silk fibers. The abundance of (13)C incorporated from the environment was determined by mass spectrometry and (13)C NMR measurements. Atmospheric CO(2) was incorporated into the silk fibers in the carbonyl groups of alanine, aspartic acid, serine, and glycine and the C(gamma) of aspartic acid. We show a simple model for the uptake of atmospheric CO(2) by silkworms. These results will demonstrate that silkworm has incorporated atmospheric CO(2) into silk fiber via the TCA cycle; however, the magnitude of uptake into the silk fibers is smaller than that consumed by the photosynthesis in trees and coral reefs.

Isotopic fractionation with morphological change and sexual specificity in the lappet moth Euthrix potatoria

“…In the case of Bombyx mori L., which is closely related to the Lasiocampidae, atmospheric carbon dioxide (CO 2 ) is fixed by proteins in the silk. Moreover, the 13 C concentration of silk increased depending on ambient 13 C levels during an experiment using 13 C labelling (Magoshi et al., , ). It remains unclear whether cocoons selectively fixed more 13 C than 12 C in this experiment, but the results suggest that the δ 13 C values of cocoons change through atmospheric C fixation.…”

Proteome analysis of silkworm 1. Fat body

“…The proteins (158 and 164) The function of the protein (253) that had similarities to the nif-like protein is unknown in FBs. Although carbon intake from air in silkworms has been reported 20) , there are no reports on nitrogen intake in silkworms, and this protein is unlikely to be involved in nitrogen fixation activities in silkworm FBs.…”

Influence of CO 2 on the micro-structural properties of spider dragline silk: X-ray microdiffraction results

“…Environmental agents such as CO 2 or N 2 are known to alter the mechanical properties of Nephila dragline silk (Work 1976;Madsen and Vollrath 2000). While atmospheric CO 2 is incorporated into silk fibroin of Bombyx mori or Nephila clavata via metabolic pathways (Magoshi et al 2003), under anaesthetizing conditions a lower breaking strain and breaking energy of the fibre was observed (Madsen and Vollrath 2000). The onset of anaesthesia also results in an increase of fibre diameter.…”